Flight Instruments Flashcards
What is the Altimeter?
A device which senses the normal decrease in air pressure that accompanies an increase in altitude.
Altimeters are calibrated to ISA, True or False?
True
If local pressure and temperature gradients do not follow ISA assumptions, errors can occur. True or False?
True
What is the VSI?
The vertical speed indicator?
What does the VSI show?
The rate of climb/decent in feet per minute.
How many feet is the VSI dial calibrated in?
100ft/minute (up or down)
Due to lag in the instrument, several seconds of steady climb/descent or level flight must elapse before an accurate reading is displayed. True or False?
True.
What is an ASI?
An air speed indicator
What is the white arc for?
Flap operating speeds
What is the green arc?
Indicates normal operating speeds.
What is the yellow arc?
Caution
What is the red sash on the ASI?
Never exceed
How does the ASI measure your speed?
Measures the difference between static pressure (usually from a sensor not in the airstream) and dynamic pressure received from the pitot tube
When the aircraft isn’t moving the pressures are equal to?
Zero and is the airspeed
Pitot =
Static + dynamic pressure
By subtracting static pressure, the ASI can indicate the speed at which the aircraft moves through the air.
True
What errors does the ASI suffer from?
Instrument
Position
Density
Compression
What is compression error?
speeds of 300+kts suffers effects of compression
What is Density error?
Air Density decreases with altitude. As aircraft climbs there is less air pressure in the pitot tube. Therefore, reading of airspeed decrease with height(although aircraft may be traveling at the same speed through the air)
When are IAS and TAS roughly the same?
Near sea level
What are Position errors?
When the pitot isn’t getting air in. Pitot should always point directly into relative airstream.
What are instrument errors?
Instruments have small imperfections caused by friction/mechanical. Corrections can be applied by reading off a correction table.
What is a Mach Meter?
A device used to show a Mach number
The speed of sound is directly related to the temperature of the air through which it travels.
True or False?
True
What errors instruments are used in combination for the Mach meter?
ASI and Altimeter
What errors does the Mach meter suffer from?
Same as the ASI and Altimeter
What is inertia?
The tendency of the gyro to keep a fixed position in relative space
What is precession?
When a subjected to a force, the gyro acts as though the force has been applied at 90 degrees to the rotor, at a position 90 degrees forward in the direction of rotation of the rotor
What does the turn and slip indicator utilise?
The gyros property of precession ( when it is tilted it turns) it can be set up to react to a turn
Define a Rate one turn
Described as 3 degrees/second
360 degrees in 2 minutes
If the balance ball rolls in the opposite direction to the turn it indicates a?
Skid
If the balance ball rolls in the same direction as the turn indicator it indicates a?
Slip
The artificial horizon employs the gyro property of inertia. True or False?
True
The artificial horizon’s gyro is tied by gravity to keep the same position relative to the centre of the earth.
True or False?
True
What is a flight director?
An artificial horizon with command bars
Will pilots use the AH/FD with other equipment and which ones?
Yes
VSI
Altimeter
What errors does the flight director suffer from?
When accelerating indicates a small nose up indication
A similar effect is observed in a tight turn
Does the magnetic compass require external power?
No
Does a magnetic compass suffer from deviation error?
Yes
What causes deviation error?
Suffers from a/c electrical equipment, metal structure, rotating propeller.
Iron metallic components.
What is deviation?
The error induced in a compass by local magnetic fields; creating compass north.
Compasses are checked at what degree increments?
30 degrees
How is deviation minimised?
Compass correction card
What is dip error?
Compass aligns itself with earth’s magnetic field. At or near the equator. Aircraft nears either magnetic pole s and the lines of force dip into the ground. Compass needle points down instead of staying near the horizon
What is acceleration error?
Occurs during airspeed changes and is most apparent on headings of east and West.
What does ANDS stand for?
Acceleration north, deceleration south
What is the Gyrosyn Compass?
A combination of a gyro and magnetic compass
The gyroscope is continuously aligned with magnetic north by a magnetic flux detector. True or False?
True
What causes Position errors?
When flying at low airspeed/ high AoA
